1. Field of the Invention
This invention relates to clarification of beverages such as beer and wine, and, more particularly, to a premix composition and process for effecting such clarification in an efficient and advantageous single-step process.
2. Description of the Prior Art
Non-biological haze in unstabilized beer arises from complexation of haze-sensitive proteins and haze-producing polyphenols and tannoids. Accordingly, silica gels such as hydrogel or xerogel have been used for effecting clarification of beer by adsorbing haze-sensitive proteins. However, silica hydrogel contains greater than 30% water and is therefore prone to microbial growth on storage. Silica xerogel contains only 5% water but becomes compacted upon hydration. Crosslinked polyvinylpyrrolidone (PVPP) also has been effective for treating unstabilized beer by specific adsorption of condensed and polymeric polyphenols and tannoids present in beer. Sequential treatments with silica gels and PVPP have been used with some measure of success. Combinations of silica hydrogel and PVPP for a single treatment process have been considered but when hydrated such an admixture becomes voluminous and clumpy making it difficult to pump homogeneously. Similarly, the industry has warned that xerogel and PVP should never be present simultaneously, as they may neutralize each other's effects.
The prior art is represented by the following U.S. Pat. Nos.: 2,316,241; 3,117,004; 3,163,538; 3,413,120; 3,512,987; 3,554,759; 3,617,301; 3,818,111; 3,903,316; 4,166,141; 4,820,420; 4,910,182; and by the following, foreign patents and technical publications:                (1) Gorinstein, S et al, J of Food Biochemistry 14, 161–172 (1990).        (2) Boschet, G. Brauindustrie 70 (16) 1441–4 (1985).        (3) McMurrough, I. et al J. Am. Soc. Brewing Chemists 50 (2) 67–76 (1992).        (4) GB 1,151,476 ('69) Deutsche Gold (silica+PVP).        (5) Weyh, H. Inst. Chem. Tech. Anal. Chem. 8050 (1987).        (6) Boschet, G. Bios (Nancy) 17 (8–9) 49–52 (1986).        (7) Birkner, F. EPA 183162 A2 Jun. 4, 1986 EP 85114640 (Nov. 18, 1985).        (8) Hums, N. DE 3509892A1 Sep. 25, 1986.        (9) Buchvarov, V. Monatsschr. Brauwiss 39 (5) 188–92 (1986)        (10) Wackerbauer, K. Monatsschr. Brauwiss 37 (5) 201–7 (1984).        (11) Chi, C. W. DE 3302258A1 Jan. 25, 1983.        (12) Jaeger, P. Mitt. Versuchsstn Gaerungsgewerke Wien 34 (9–10) 83–9 (1980).        (13) Sfat, M. R. Tech. Q, Master Brew Assn Am 12 (4) 243–8 (1975)        (14) Silbereisen, K. Monatsschr. Brauwiss 21 (8) 221–35 (1968).        (15) Schafft, H. Brauwelt 117 (36) 3–7 (1977).        (16) Blecher, L. Brew. Dig, 51 (7) 33–5, 44 (1976).        (17) Grace, DE 3302258A1 (1983).        (18) Chi, C. W. Can. Pat. 1,178,222.        (19) Suhner, Ger. Pat. Publicn. 1907610, C.A. 75, October 1972 (p. 2/6) QD 1A5.        
However, none of these references disclose a composition for clarifying beer or wine in an efficient and advantageous manner with a premix composition of a silica xerogel having defined characteristics present in a predetermined amount with a crosslinked polyvinyl lactam polymer.
Accordingly, it is an object of the present invention to provide a new and improved premix composition of a siliceous material and crosslinked polyvinylpyrrolidone for use in clarification of beer or wine.
Another object herein is to provide a stable premix composition for clarification of beer or wine which has a long shelf life and is not prone to microbiological contamination.
Still another object of the invention is to provide a stable premix composition of a siliceous material and a crosslinked polyvinyl lactam which is effective for colloidal stabilization of beer.
Among the other objects herein is to provide such a premix composition which can efficiently remove sensitive proteins, polyphenols, flavanoids and tannoids from beer, and to effect a substantially complete reduction in chill haze in the beer.
Yet another object herein is to provide a process for colloidal stabilization of beer in a single dosing and a single filtration operation.
A specific object herein is to provide a stable premix composition which is selective to removal of high molecular weight proteins while leaving the desirable low molecular weight proteins remaining in the clarified beer.
A feature of the present invention is the provision of a stable premix of predetermined composition which is a siliceous xerogel material having less than about 10% by weight of water therein, and a particle size as defined by its mean volume average diamter, Mv, of less than 50μ, both in the dry state and as a 10% aqueous slurry, and a crosslinked polyvinyl lactam, preferably crosslinked polyvinylpyrrolidone (PVPP), in a weight ratio of about 40 to 90% of the xerogel to about 10 to 60% of PVPP, for effective clarification of beer.
These and other objects and features of the invention will be made apparent from the following description of the invention.